1. Field of the Invention
This invention relates to arrowheads that have opening blades, and more particularly to non-consumable blade retention for retaining a pivotal blade of a blade-opening arrowhead in the retracted position by methods that are not dependent upon the use of an element or elements in addition to that individual cutting blade, its hinge pin and its blade slot, so that when the arrowhead penetrates an object the blade freely rotates to an open position.
2. Description of Prior Art
Arrows have long been used for war, hunting and competitive sports. A conventional arrow has a shaft, a nock at one end that receives the bow string, an arrowhead or point that attaches to the opposite end, and fletchings. The fletchings are glued to the shaft near the nock end, and help to stabilize the arrow in flight, as it rotates. Arrowheads generally have a pointed forward end, and an opposite threaded shaft end that attaches the arrowhead to the arrow shaft. Arrowheads are also attached to the forward end of arrow shafts by glueing and other methods.
Arrowheads come in a variety of different sizes and configurations depending on their intended use. For example, there are specifically designed arrowheads for competitive target shooting, shooting fish, hunting birds or small game animals, and for hunting big game animals.
The most common type of arrowhead used in hunting is the fixed-blade arrowhead, which has a pointed tip end used for penetrating, and fixed blades or non-pivotal blades that each have a razor sharp edge for cutting. Conventional fixed-blade arrowheads blades are held in a fixed position on the arrowhead, and most such blades are replaceable. The replaceable blades attach to the arrowhead body in longitudinal grooves called blade slots. The tip of the arrowhead may be separably attachable to the arrowhead body or may be integral with it. Arrowheads for hunting are generally known as broadheads.
Arrowheads used for hunting, kill the game animal by cutting vital organs such as the lungs and vascular vessels such as arteries, which causes rapid hemorrhaging and/or suffocation. Quick and humane kills are dependent on accurate shot placement, and upon the amount or volume of the animal tissue that is cut. Hunting arrowheads that cut more tissue are more lethal, and therefore are better. The volume of tissue that is cut is determined by the cutting diameter of the arrowhead, the number of blades it contains, and by the distance the arrowhead penetrates into the animal. The cutting diameter of an arrowhead is determined by how far each cutting blade extends outward from the arrowhead body. The further the blades extend outward the larger the cutting diameter is, and therefore the more cutting potential the arrowhead has.
A problem with conventional fixed-blade arrowheads is that having the desirable, large cutting diameters generally cause unstable arrow flight or poor arrow aerodynamics, which affects accurate shot placement. This can lead to non-lethal wounding of the game animal or missing the animal altogether. Unstable arrow flight in hunting arrows is generally caused by arrowhead aligning and centering problems. Arrowhead aligning and centering problems are prevalent when the arrowhead is attached to the arrow shaft such that the longitudinal axis of the arrowhead is not in line with the longitudinal axis of the arrow shaft. Alignment and centering problems in arrowheads are generally created by low tolerances or sloppiness in the manufacturing of the arrowhead body. When a mis-aligned arrowhead is attached to an arrow and the arrow is shot, as the arrow spins or rotates in flight non-stabilizing forces are induced on the front end of the arrow and cause inconsistent or erratic flight, which steers the arrow from its intended path. Since the cutting blades of fixed-blade arrowheads extend out from the arrowhead body when the arrowhead is in flight, the blades greatly magnify any non-stabilizing forces induced on the arrow from mis-alignment, and therefore increase erratic arrow flight. This in the main reason why conventional fixed-blade arrowheads are limited in the maximum cutting diameter they can have, while retaining sufficiently stable aerodynamics.
To create a hunting arrowhead that has both a maximum cutting diameter and stable aerodynamics, despite moderate manufacturing tolerances, blade-opening arrowheads were designed. Blade-opening arrowheads differ from conventional fixed-blade arrowheads in that the cutting blades are folded up or held adjacent to the arrowhead body in a retracted position while the arrow is in flight, but at impact with the game animal rotate or pivot into an open position, therefore exposing the sharp blade edges and cutting the animal. Since the blades of blade-opening arrowheads are held adjacent to the arrowhead body and do not extend very far out from it, any aligning or centering problems of a blade-opening arrowhead attached to an arrow will not noticeably steer the arrow or undesirably affect its flight trajectory. In this manner blade-opening arrowheads can have both a desirable large cutting diameter, and the stable arrow flight characteristics necessary for accurate shot placement. Blade-opening arrowheads can therefore potentially be more lethal.
Blade-opening arrowheads, like conventional fixed blade arrowheads generally have an elongated arrowhead body, a tip end, and a threaded opposite end. The blades of blade-opening arrowheads have an attachment end which attaches the blades to the arrowhead body by a pivot pin, so that the blades can pivot or rotate in a plane between a first selectable positionxe2x80x94the retracted position, and a second selectable positionxe2x80x94the open position. Blade-opening arrowheads also come in a variety of different types and styles. The blades of the most common type of blade-opening arrowheads, when in the retracted position have a leading blade end positioned near the tip of the arrowhead that protrudes outward from the arrowhead body, and is sometimes shaped like a wing. The leading blade ends of the most common type of blade-opening arrowheads, rotate away from the arrowhead body in a rearward direction when penetrating an animal. Particularly, the leading blade ends catch on the animal""s surface and serve to lever or rotate the blades into the open position, thus exposing the sharp cutting edges of the blades and cutting the animal. The blades of blade-opening arrowheads are also received in blade slots, which are machined or formed into the side of the arrowhead body.
Blade-opening arrowheads for hunting big game must be non-barbing, wherein the blades when in the open position must not inhibit or prevent arrow extraction from a game animal by barbing into the animal tissue. This makes it so non-fatally wounded animals can easily pull out an arrow still lodged in them. For a blade-opening arrowhead to be non-barbing, the pivotal blades must rotate forward from the open position to an angle greater than ninety degrees, as measured between the rear edge of each blade and a location on the arrow shaft rearward of the blades.
Blade-opening arrowheads generally do not penetrate as deep as conventional fixed-blade arrowheads. This has a variety of causes, one in particular occurs when the blades are non-radially aligned with respect to the longitudinal axis of the arrowhead body such that a net pulling force is exerted on each blade when penetrating an object which causes the arrowhead to spin or twist. Spinning reduces penetration by driving the flat blade sides into uncut tissue, which causes friction and therefore depletes kinetic energy that could otherwise further penetration. Non-radial blade alignment is created when the blades are not situated in line with a radius line extending from the longitudinal center of mass of the arrowhead body or the longitudinal axis, to the exterior surface of the arrowhead body. The rate of spin or the spin capacity of conventional blade-opening arrowheads is limited to the extent of the pulling force exerted upon on the arrowhead body by non-radial aligned blades.
Reduced penetration in blade-opening arrowheads can be both desirable and undesirable depending on the type of game animal hunted and the type of wound channel desired. Reduced penetration from spinning when hunting big game animals is generally undesirable, unless the archer is shooting an extremely powerful bow and complete arrow pass-through is assured, and then a twisted wound channel with possibly more tissue damage may be desirable. Reduced penetration from spinning in blade-opening arrowheads for hunting wild turkeys and other small game animals is very desirable since an arrow lodged in a wild turkey greatly limits the distance the bird can retreat after being shot. Therefore reduced arrow penetration aids in increasing the recovery rate of arrowed small game animals.
To hold the blades of blade-opening arrowheads in the retracted position during flight until the arrowhead penetrates the animal, annular retention members such as O-rings are most commonly used. Other commonly known annular retention members are, rubber bands, tight fitting plastic sleeves, tape, heat-shrinkable fitting plastic sleeves, and other wrap materials. When the O-rings are stretched around the outside of the blades they exert a resistive force against the blades and hold the blades selectively in the retracted position.
O-ring use for blade retention is less than ideal. The elastomeric polymer materials are susceptible to drying-out and therefore cracking, which can lead to breaking of the O-ring during arrow acceleration when the arrow is shot. This will cause premature blade-opening and produce extremely erratic arrow flight and possible non-lethal wounding of the game animal. This may also cause severe lacerations to the archer. Also, bows shooting arrows at very high speeds can require as many as three O-rings to prevent premature blade-opening. The experience of learning this can be very undesirable for the archer. O-rings are a consumable item designed for one shot use, and the cost of constantly replacing them is a detrimental factor. Also, they are not user-friendly and are a general bother to worry about while out in the field.
Aside from consumer use considerations, humaneness to the hunted game animal is an important consideration as well. When the arrowhead penetrates the animal and the blades begin to rotate open, the more the O-ring is stretched the more resistive force it exerts back against the blades, thus impeding the rate of blade-opening. This can possibly prevent full blade-opening and a quick and humane kill. Also, extreme weather temperatures greatly affect the elasticity of O-rings; cold weather decreases elasticity which increases the likelihood of the blades not opening, and hot weather increases elasticity which increases the likelihood of premature blade opening.
Attempts in the prior art have been made to remedy the problems associated with O-ring use for blade retention of blade-opening arrowheads, but these attempts have their own problems as well. For example, the use of magnetism for blade retention is known to the art. The disadvantages of using magnets for blade retention are that magnets are heavy, relatively expensive, and can demagnetize. Also known to the art for retaining a pair of blades commonly mounted on a pivot pin in a single blade slot where the blades rotate to opposing sides of the arrowhead body substantially 180 degrees apart when in the open position, is the use of a blade slot that has a narrower opening between opposing blade slot sidewalls at the forward limiting end of the blade slot, where the opening is wider than the width of a blade, such that each blade is biased when in the retracted position. A disadvantage of such narrower blade slot blade retention is that according to such a design a single individual blade cannot be retained in the retracted position without the interaction of the other blade. This means that for producing a desirable, maximum diameter cut from more than two opened blades distributed substantially equidistantly about the perimeter of the arrowhead body, such as the more lethal very popular three blade 120 degree displaced blade design, from such a narrower blade slot blade retention design, requires having two layers of blades or blade slots. Having to accommodate two layers of blade slots in an arrowhead body is a major disadvantage since it will add a significant amount of mass to the arrowhead body and thus decrease arrow velocity, which is in direct contrast to the current strong market trend for fast, flat-shooting arrows. Also commonly known to the art for retaining a blade in the retracted position is the use of an element or elements in addition to that cutting blade, its blade slot and its pivot pin. Examples of such required additional elements for blade retention are: spring elements such as leaf springs or cantilevers, shear rods, O-rings, and another blade. Disadvantages of using additional elements for blade retention are, increased cost, decreased user-friendliness, manufactural complexity, and increased probability of malfunction since the more parts required to perform a function the greater likelihood there is for failure. Disadvantages of other blade retention methods known to the art are, reduced penetration of the arrowhead, structural weakening of various arrowhead elements, in-operability, and manufactural unfeasibleness.
It is apparent that there are much needed improvements in blade-opening arrowheads, both in consideration of the archery consumer and the hunted game animal.
It is apparent that there is a need for a blade-opening arrowhead that securely holds each blade selectively in a retracted or in-flight position, in a secure or locked manner by methods other than O-rings or similar consumable elements.
It is also apparent that there is a need for a blade-opening arrowhead that securely holds each blade selectively in a retracted or in-flight position, in a secure or locked manner, by methods that utilize a minimal number of parts so as to be manufacturally simple, cost effective, structurally strong, user-friendly and to therefore reduce the probability of failure.
It is also apparent that there is a need for a blade-opening arrowhead that is capable of providing increased spinning so as to decrease penetration sufficiently to prevent complete arrow pass-through in wild turkeys, especially when shooting the popular, powerful, flat shooting, and accurate bows.
It is yet further apparent that there is a need for a blade-opening arrowhead that is capable of providing increased spinning so as to provide a more traumatized and damage inflicted wound channel.
It is one object of the present invention to provide blade-opening arrowheads with blade retention methods that do not require the use of consumable elements such as O-rings.
It is another object of the present invention to provide blade-opening arrowheads that require a minimum number of parts or elements for blade retention so as to be manufacturally simple, cost effective, structurally strong, user-friendly and to therefore be less susceptible to failure.
It is another object of the present invention to provide blade-opening arrowheads having a plurality of blades, where each blade is independently securely held selectively in a retracted in-flight position, in a secure or locked manner.
It is another object of the present invention to provide blade-opening arrowheads that securely hold each blade selectively in a retracted in-flight position, in a secure or locked manner where a rigid non-flexible bias element cams each blade within its respective blade slot so that each blade is securely held adjacent to the arrowhead body by frictional engagement when in the retracted position.
It is another object of the present invention to provide blade-opening arrowheads that securely hold each blade selectively in a retracted or in-flight position, in a secure or locked manner where the plane each blade rotates in is not parallel to a partially bounding sidewall of the blades""s corresponding blade slot, such that each blade biasly engages against the sidewall and is securely held adjacent to the arrowhead body by frictional engagement when in the retracted position.
It is another object of the present invention to provide blade-opening arrowheads that securely hold each blade selectively in a retracted or in-flight position, in a secure or locked manner where each blade engages with a corner formed at the juncture of the exterior surface of the arrowhead body and a partially bounding sidewall of each blade""s corresponding blade slot, so that each blade is securely held adjacent to the arrowhead body by frictional engagement when in the retracted position.
It is another object of the present invention to provide blade-opening arrowheads that securely hold each blade selectively in a retracted or in-flight position, in a secure or locked manner where the opening between opposing sidewalls of each blade slot is wider toward the forward end of the blade slot, and where a rigid non-flexible bias element cams each blade within its respective blade slot so that each blade is securely held adjacent to the arrowhead body by frictional engagement when in the retracted position.
It is still another object of the present invention to provide blade-opening arrowheads that securely hold each blade selectively in a retracted or in-flight position, in a secure or locked manner where the opening between opposing sidewalls of each blade slot for at least a portion of the blade slot is narrower than the thickness of a blade when a blade is not retracted therein, wherein when each blade is retracted into the retracted position the sidewalls of its blade slot are flexed so that each blade is securely held adjacent to the arrowhead body within its blade slot by frictional engagement.
It is still another object of the present invention to provide blade-opening arrowheads that securely hold a pair of blades in a single blade slot selectively in a retracted or in-flight position, in a secure or locked manner where the opening between opposing sidewalls of the blade slot for at least a portion of the blade slot is narrower than the thickness of both blades when the blades are not retracted therein, wherein when the blades are retracted into the retracted position the sidewalls of the blade slot are flexed so that the blades are securely held adjacent to the arrowhead body within their blade slot by frictional engagement.
It is yet further another object of the present invention to provide blade-opening arrowheads that provide increased spinning capacity, thus to provide a more traumatized wound channel, and/or to reduce penetration such to prevent complete arrow pass-through in wild turkeys and other small game animals, particularly when using powerful, accurate, flat-shooting bows.
The foregoing objects and advantages and other objects and advantages of the present invention are accomplished with a hunting arrowhead that attaches to the forward end of an arrow shaft, where a plurality of blades are pivotally or hingedly connected to an arrowhead body. The blades freely rotate in a plane from an in-flight retracted first selectable position to an open second selectable position when the arrowhead penetrates an object, or when acted upon by a sufficient opening force.
Such a blade-opening arrowhead according to one preferred embodiment of this invention has an arrowhead body with a tip end used for initial penetration and an opposing threaded shaft end that screws or threads the arrowhead to an arrow. The tip end may be removably attached to the arrowhead body, and may be made of material different than the rest of the arrowhead body. The arrowhead body has a plurality of three blade slots substantially equally distributed 120 degrees about the perimeter of the arrowhead body, with one blade in each respective blade slot. Each blade has a first end, an opposing second end, a face extending between the ends on each blade side, and an edge extending about its periphery. One blade edge of each blade is sharpened for cutting. The first blade ends or the leading ends each have a protruding wing that is exposed out from the arrowhead body when the blades are in the retracted position. The wings serve to increase the moment-arm for levering or rotating the blades to the open position. The second end of each blade has an aperture or hinge pin receiving hole for receiving a pivot pin or a hinge pin. The arrowhead body also has a hinge pin receiving hole for each blade. The arrowhead body hinge pin receiving holes are recessed or drilled into the two opposing sidewalls of each blade slot, and are threaded to receive the threaded hinge pins. A single hinge pin is used for each blade, and when the blades are positioned in the blade slots, each hinge pin is extended through the aperture of a corresponding blade and is screwed into the arrowhead body. This pivotally connects the blades to the arrowhead body, so that each blade rotates in a plane between the retracted position and the open position. The hinge pin receiving holes are drilled non- perpendicularly to the blade slot sidewalls, but the hinge pins extend perpendicularly through the blades when extended through the apertures of the blades when the blades are mounted to the arrowhead body. This makes it so that the plane that each blade rotates in is not parallel to the sidewalls of its corresponding blade slot. The openings between the sidewalls of the blade slots are wider than the blade thickness so that when the blades are folded up into the blade slots in the retracted position, a face or side of each blade biasly engages against a rigid, non-flexible sidewall and each blade is camed or flexed such that it remains independently securely held selectively in the retracted position by frictional engagement without the use of any element or elements in addition to that respective blade, its blade slot and its hinge pin. This makes a very simple to use and effective blade-opening arrowhead because, there are no additional elements to hassle with, a large diameter preferably more than two blade cut wound is attainable, and the arrowhead has no unnecessary weight and therefore provides more accurate or flatter-shooting arrows. The force generated from caming or flexing each blade is strong enough to maintain the blades in the retracted position when the arrow is exposed to incidental forces, such as those produced from transporting the bow, nocking an arrow to the bow string, and acceleration when the arrow is shot, but is weak enough, to be easily overcome when the arrow impacts or begins to penetrate a game animal. The width of the blade slot openings are wide enough to allow the blades to freely rotate to the open position and to seat within the blade slot when in the open position with a snug and wobble-free fit. When rotated to the open position the blades abut against the arrowhead body, thus defining the cutting diameter of the arrowhead.
The plane each blade rotates in, or is in when in the open position, may be parallel to the longitudinal axis of the arrowhead body or may be non-parallel to the longitudinal axis of the arrowhead body depending on the angular orientation the blade slots are machined or fabricated within the arrowhead body. When the opened blades are aligned non-parallely to the longitudinal axis of the arrowhead, the arrowhead will spin when penetrating an object since a flat blade face or side of each blade will be angled or inclined such that the inclined faces are exposed in the forward direction the arrowhead is traveling. This will make it so the inclined faces contact uncut tissue such that a net force will be produced perpendicularly to the longitudinal axis of the arrowhead and thus cause the arrowhead to spin. Modifications in the machining or fabricating process of the arrowhead body blade slots that produce different inclination or sloped orientations of the opened blades with respect to the longitudinal axis of the arrowhead body, will produce blade-opening arrowheads that have different spin capacities. This variability in the amount of spinning capacity makes it possible to produce blade-opening arrowheads with reduced arrow penetration sufficient enough to prevent complete arrow pass-through in wild turkeys when shooting the very popular, powerful, and therefore accurate, and flat-shooting bows. This spinning capacity is also capable of producing a twisted wound channel with potentially more trauma and damage being done to the cut tissue within the channel""s path.
Blade-opening arrowheads according to other preferred embodiments of this invention differ from the above described preferred embodiment in that the face of each blade biasly engages against an exterior corner formed at the juncture of a blade slot sidewall and the exterior surface of the arrowhead body. Each blade slot sidewall of each engaging corner is sloped relative to the plane its respective blade rotates in such that the leading ends of the blades intersect with the corners when the blades are folded into the retracted position. The radial alignment, with respect to the longitudinal axis of the arrowhead body, of the sidewalls of each blade slot is substantially non-parallel to the radial alignment of the plane that each respective blade rotates in such that each blade is diagonally disposed within its blade slot when in the retracted position so that an inside angle is formed between the face of each blade and the corresponding blade slot sidewall. According to one such embodiment the face of each blade has a recess formed in it such that when the blades are in the retracted position the recesses receive the corners thus independently securely holding each blade selectively in the retracted position. According to another such embodiment the face of each blade has a rigid, non-flexible knob protruding from it such that when the blades are in the retracted position the knobs bias against the corners thus independently securely holding each blade selectively in the retracted position. Particularly the knobs bias against the sidewalls of the blade slots medially to the corners, as determined with respect to the longitudinal axis of the arrowhead body.
Blade-opening arrowheads according to other preferred embodiments of this invention differ from the above described preferred embodiments in that the width of the blade slot opening between opposing sidewalls is larger toward the forward end of the blade slot, and the plane each blade rotates in is parallel to the sidewalls of its blade slot. According to such embodiments a rigid non-flexible bias element protrudes out from either each blade face or from a sidewall of each blade slot and serves to cam or flex each blade within its blade slot, thus independently securely holding each blade selectively in the retracted position by frictional engagement. The bias element of the blades and blade slot sidewalls are integrally formed thereupon.
Blade-opening arrowheads according to yet other preferred embodiments of this invention differ from the above described preferred embodiments in that the sidewalls of the blade slots are flexible or resilient, preferably being molded of a composite resin. According to one such embodiment, each blade slot has a slot opening width between opposing blade slot sidewalls for at least a portion of the blade slot that is narrower than the thickness of a blade, as determined when the blades are not positioned in the blade slots in the retracted position. Each blade also rotates in a plane substantially parallel to the sidewalls of its blade slot. According to such embodiment, when each blade is folded up into the retracted position between the resilient sidewalls of the blade receiving slots, the slot sidewalls are flexed and each blade is thus independently securely held selectively in the retracted position by frictional engagement.
When the arrowheads according to the above described preferred embodiments of this invention initially penetrate an animal, the first ends or leading ends of the blades catch on the animal""s surface and the blades are easily levered out as the frictional engagement is overcome, whereupon the blades freely rotate toward the open position. All that is required to securely re-lock the blades back in the retracted position, is to simply push each blade back into the retracted position, whereupon the frictional engagement selectively retains each blade in the retracted position. There is no requirement to spend additional time and effort handling other elements.
The blade-opening arrowheads according to this invention, use no consumable items such as O-rings, for blade retention. The blade-opening arrowheads according to this invention provide blade retention methods that require less parts or elements than prior art blade-opening arrowheads. This provides blade-opening arrowheads which are more cost effective, simpler to manufacture and to use, and less susceptible to failure. The blade-opening arrowheads according to this invention provide blade retention methods that are not suspectable to malfunctioning when exposed to the harsh conditions commonly encountered in the field, and when subjected to prolonged use. The blade-opening arrowheads according to this invention are also structurally strong, and operable.
The blade-opening arrowheads according to this invention provide increased spinning capacity which can create a more traumatized wound channel, and reduce penetration sufficiently to prevent complete arrow pass-through in wild turkeys and other small game animals even when using powerful, accurate, flat-shooting bows.
As has been shown in the above discussion, the blade-opening arrowheads according to this invention overcome deficiencies inherent in prior art arrowheads.
With the above objects and advantages in view, other objects and advantages of the invention will more readily appear as the nature of the invention is better understood, the invention is comprised in the novel construction, combination and assembly of parts hereinafter more fully described, illustrated, and claimed.